By Eleanor McDermid, Senior medwireNews Reporter
Mortality after general anesthesia has declined over the past 50 years, but the greatest gains have been in developed countries, shows a systematic review in The Lancet.
Mortality related directly to general anesthesia has fallen almost 10-fold since before the 1970s, report Daniel Bainbridge (University of Western Ontario, London, Canada) and colleagues.
This was despite the fact that mortality risk rose in line with poorer baseline American Society of Anesthesiologists (ASA) status and that patients' average ASA status grew worse over the period of study.
In developed countries, the weighted mortality event rate was 357 per million before the 1970s, falling to 32 per million in the 1970s to 1980s. There were no data available for developing countries before the 1970s, but in the 1970s to 1980s the event rate was 101 per million - markedly higher than that in developed countries.
By the 1990s to 2000s, the event rate in developed countries had fallen, to 25 per million, but that in developed countries had not, at 141 per million.
In a commentary accompanying the paper, Michael Avidan (Washington University School of Medicine, St Louis, Missouri, USA) and Sachin Kheterpal (University of Michigan Medical School, Ann Arbor, USA) say: "Fortunately, many of the recent gains in patient safety in developed countries are based on process improvement, not expensive technologies.
"For example, the Safe Surgery Saves Lives Study, undertaken under the banner of [the World Health Organization], showed that a structured checklist, with simple interventions spanning the perioperative period, could markedly affect mortality and improve surgical outcomes."
The analysis by Bainbridge et al is based on 87 studies, incorporating data for more than 21.4 million anesthetic administrations. For total perioperative mortality, defined as death within 48 hours of surgery, rates in developed and developing countries were 10,603 and 11,378 per million, respectively, before the 1970s.
Rates for both groups of countries declined thereafter, to 1982 and 7336 per million, respectively, in the 1970s and 1980s, and to 1095 and 2445 per million, respectively, in the 1990s and 2000s.
Again, the rates were generally higher in developing than developed nations.
But Avidan and Kheterpal warn against complacency in developed countries, saying that the "procedure-centric" definition of perioperative mortality used in the study "belies the reality of perioperative patient outcomes."
This suggests that "in developed countries some of the early perioperative mortality has simply been deferred," they say.
"There probably remains an unexpected and poorly measured pandemic of perioperative mortality, which is an unappreciated public health concern. What proportion of these deaths could be averted with optimum perioperative management is unknown."
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